A shell-and-tube type heat exchanger of the smallest possible length necessary for heat exchange is disclosed which is capable of obtaining uniform distribution of flow of a shell side fluid and substantially eliminating the structural restriction imposed on the shell side. This shell-and-tube type heat exchanger is provided with one annular conduit furnished with not less than two partitions concurrently serving as an expansion joint for introducing and discharging a shell side fluid and allowing the flow path for said shell side fluid to be separated into an introducing part and a discharging part and which comprises a place having no array of heat-transfer tubes in the flow path for said shell side fluid. It prevents the equipment from necessitating an unnecessary enlargement due to the structural restriction on the shell side and enables the shell side fluid to produce a uniform flow.